Her menses started after the time for Zuhr began; should she make it up when her period is over?
If a Woman gets her menses and she didn’t pray Isha for example, scholars say that she must make this prayer up when she is pure. However, this was never reported from any of the female companions doing this. Besides, most women after seven or eight days would forget whether they had missed a prayer or not.
Therefore, it seems to me that she is not sinful and she is not obliged to make it up.